Congratulations! You are now the proud owners of a rooftop photovoltaic system that collects electricity quietly and cleanly as you shop. As a Willy Street Co-op member, you can take pride in the fact that each year this system will:

• Convert 5,100 kilowatt hours of the sun’s energy into electricity
• Save $550 (and more each year!) on energy bills
• Cut coal burning by 4,200 pounds.
• Conserve 2,200 gallons of power plant-cooling water
• Slow global warming by keeping 12,000 pounds of CO2 out of the air
• Decrease acid rain by keeping 70 pounds of SO2 out of the air
• Reduce local mercury emissions
• Demonstrate the Co-op’s leadership in environmental stewardship
• Help educate the community on the benefits of renewable energy

This system has been actively converting the sun’s energy into electricity since March 2nd. The rooftop equipment consists of 22 Kyocera photovoltaic panels, each of which is capable of producing 167 Watts of power, for a total of 3,674 Watts (enough to power two efficient households). The angle the panels face is adjustable so that as the season changes we can optimize their performance. The system includes two inverters that convert the DC power the system collects into AC power we can use. These inverters also log information about how the system is performing. The inverters have some additional capacity which will make it easy to someday expand the system. Finally, there is a meter in the entryway that tells us how much energy we are converting and how much money we are saving. To see how much energy we’ve collected so far and how much money we’ve saved, log onto our website at http://www.willystreet.coop/about/solar.htm. One thing the system doesn’t include is batteries; it is set up so that any power we don’t use will be fed into the electricity grid. This significantly reduced the complexity and cost of the system by avoiding the need for battery storage.

Investing in our future
We spent only $16,700 for the entire system, thanks to a grant of $9,006 from Wisconsin Focus on Energy (http://www.focusonenergy.com/), a state program that encourages renewable energy and energy efficiency. Focus provided excellent technical advice and an independent perspective during the planning stages of this project. A long-term financial investment for the Co-op, the photovoltaic system is anticipated to pay for itself in about 17 years, assuming a 5% energy inflation rate. Burke O’Neil from the local company Light Energy Systems supplied and installed our new equipment.
One of our goals with this project is to educate the community about renewable energy technologies. We are planning educational displays in the store, as well as on our web site.

Using the meter in the entry area shoppers can easily see how much energy the system is producing and how much money we are saving. Check it out next time you’re in the store! The meter will be directly in front of you and a little to the right as you come in the front door. Future plans include providing updates about our system on our web site. If you want to know how photovoltaic systems actually work, you can find a good explanation at: http://www.nesea.org/buildings/
info/solarelectricity.html.

Saving energy and achieving our goals
In addition to procuring our own electricity, we have worked hard to make your store more energy efficient. When we renovated our current space we paid a lot of attention to energy efficiency; we installed energy efficient lighting and occupancy sensors, high efficiency refrigeration systems, a bit of day-lighting where we could make it work, heat reclaim systems, energy-star certified equipment, and low-flow water fixtures. We also strive to buy as much local food as we can, greatly reducing the energy used for transportation and intermediary storage.

Nevertheless, the Co-op’s average monthly electricity consumption is 66,300 kilowatt-hours costing $5,300 per month. We will continue to work to make our store as energy efficient as possible, but keeping all our yummy food cool, lit, and in a comfortable environment takes a lot of energy!

A handful of you are aware that using renewable energy has been a goal of the Co-op’s since we started planning our move into our current site in 1998. We hoped to use our new building as an example of sustainability. We meet some of our electricity needs with wind power purchased from MG&E. But, during the move and since, financial considerations kept the photovoltaic project in the dream stage. Every year during our budgeting process we’ve asked ourselves if we’d achieved the financial stability necessary to pursue further greening of our facility. Our success—your seemingly ever-expanding patronage—has finally made this worthy goal attainable. Thank you!

Buying photovoltaic systems in Madison
For those who are interested in pursuing photovoltaics for your home or business, the Co-op took bids from three PV installers who serve our community.

• Seventh Generation Energy Systems: http://www.seventhgenergy.org/
• Light Energy Systems: http://www.lightenergysystems.com/
• H&H Electric: http://hhelectric.com/ABOUT THE AUTHOR: Jamie Campbell volunteered on the ad-hoc expansion committee that steered us to our current location, advocating green building strategies during the renovation. More recently, he volunteered for the Co-op to help with the technical aspects of this project.